The present invention relates to a working vehicle with a laterally traveling system which can switch the working vehicle to lateral traveling.
Conventionally, a self-propelled working truck which is found in Japanese Patent Unexamined Publication No. 2-306879 is proposed as a working vehicle that can be switched to lateral traveling.
In this conventional construction, on a bottom face of a frame, two drive wheels located on one diagonal line are provided via a direction turning shaft to be turnable, while two free idler wheels located on the other diagonal line are provided to be turnable, and both the drive wheels are operatively connected to each other by a direction changing connecting part. The connecting part is constructed by turning levers provided at a side of the direction turning shaft, a pair of rods connected to these turning levers at tip ends thereof, a hydraulic cylinder provided along the diagonal line on which both the drive wheels are located, and a connecting fining which is provided at an extendable rod of this hydraulic cylinder and which connects inner ends of the pair of rods.
The drive wheels are attached to support fittings via a drive shaft, and the support fitting is provided at the frame side via the direction turning shaft to be turnable. Further, a drive motor is provided at the support fitting, and a worm gear projected downward from the drive motor is meshed with a worm wheel of the drive shaft.
According to the conventional construction as described above, by extending and contracting the hydraulic cylinder, the rods are pushed and drawn along the diagonal line via the connecting fitting, whereby both the drive wheels can be turned in the opposite direction from each other via the turning levers and the direction turning shaft. The rotation of the drive motor is transmitted to the worm gear, worm wheel, and the drive shaft, whereby the drive wheels can be rotationally driven.
However in the above-described conventional construction, the drive motor (traveling drive device) is provided to the support fitting outside the turning axis, whereby the width of the drive wheel part which is turned becomes large, and therefore a large turning space has to be secured, thus making the width (length) of the vehicle body larger and increasing the size of the entire body. The drive motor and the like are independently constructed and thereafter installed, and thus the size of the entire body is increased.
The present invention has its object to provide a working vehicle with a laterally traveling system which is of a type capable of steering drive type front wheels to turn at substantially right angles in a lateral direction while a traveling drive device section is constructed to be compact with excellent assembling easiness.
In order to attain the above object, a working vehicle with a laterally traveling system of the present invention comprises a pair of left and right front wheels and a pair of left and right rear wheels mounted to a vehicle body to be turnable by 90 degrees, the pair of left and right front wheels being attached to transmission devices mounted to the vehicle body to be rotatable around vertical axes, rotating means provided between the vehicle body and the transmission devices, and a travel-driving electric motor located under the vertical axis and attached to each of the transmission devices, and is characterized in that each travel-driving electric motor has a case body comprising an outer case part and a non-loaded side bracket, the outer case part having a loaded side end portion connected to a case body of the transmission device, one end of a drive shaft mounted with a rotor is rotatably supported by the non-loaded side bracket, and the other end is rotatably supported by the case body of the transmission device, and the other end of the drive shaft is provided with a driving portion of the transmission device, which driving portion is operatively connected to an axle.
According to the invention with the above-described construction, the loaded side end portion of the outer case part in the case body of the electric motor is connected to the case body of the transmission device, and the other end of the drive shaft is rotatably supported at the case body of the transmission device, whereby the number of the components of the electric motor is reduced to be able to simplify the construction, and the section of the electric motor is improved in assembling easiness (mounting easiness), and can be constructed to be compact. In addition, the electric motor is located under the vertical axis, whereby the width of the turning front wheel part, namely, the space for turning can be made smaller, thus making it possible to reduce the width (length) of the vehicle body and downsize the entire body.
During normal traveling, the left and right front wheels and the left and right rear wheels face the longitudinal direction. When switching from the normal traveling to the laterally traveling, the rotating means are operated first to rotate the transmission devices around the vertical axes, whereby the front wheels can be turned by 90 degrees (turned laterally at substantially right angles) with respect to the vehicle body. Here, the electric motors and the front wheels are located under the vertical axes, whereby turning of the electric motors, the front wheels and the like by 90 degrees is performed easily, smoothly and compactly. After the drive type front wheels are turned laterally at substantially right angles (steered), the front wheels are driven in the normal and reverse direction by the electric motors, whereby the working vehicle can laterally travel either to the left or right.
The preferred embodiment in the working vehicle with the laterally traveling system of the present invention is characterized in that the mast is disposed at the front end side of the vehicle body, and forks are attached to the mast.
According to this embodiment, during normal traveling, the left and right front wheels and the left and right rear wheels face the longitudinal direction, and by manipulating the lever for the lift, the fork is hoisted and lowered along the mast to perform a fork operation for a predetermined period of time. While it is of the type which enables a normal fork operation like this, it steers the drive type front wheels to face laterally at substantially right angles to make it possible to perform lateral traveling, and for example, an elongate object can be transported easily via the forks.